I'm not sure why this is happening, but Blender has been rendering an 80 frame scene with 500 samples for around 13 hours now. It started out at a decent speed, but now it's rendering at about ONE SAMPLE PER SECOND. I'm not sure what caused it to change, but it's VERY painful, and I need to get a couple more scenes done this weekend. I don't know how I'm going to make my deadline if they all end up like this...Anyone have any ideas? Thanks in advance!